Background: DNA replication in trypanosomatids operates in a uniquely challenging environment, since most of their genomes are constitutively transcribed. Trypanosoma cruzi, the etiological agent of Chagas disease, presents high variability in both chromosomes size and copy number among strains, though the underlying mechanisms are unknown.
Results: Here we have mapped sites of DNA replication initiation across the T. cruzi genome using Marker Frequency Analysis, which has previously only been deployed in two related trypanosomatids. The putative origins identified in T. cruzi show a notable enrichment of GC content, a preferential position at subtelomeric regions, coinciding with genes transcribed towards the telomeres, and a pronounced enrichment within coding DNA sequences, most notably in genes from the Dispersed Gene Family 1 (DGF-1).
Conclusions: These findings suggest a scenario where collisions between DNA replication and transcription are frequent, leading to increased genetic variability, as seen by the increase SNP levels at chromosome subtelomeres and in DGF-1 genes containing putative origins.
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http://dx.doi.org/10.1186/s12864-020-06803-8 | DOI Listing |
Nature
January 2025
Stanford Cancer Institute, School of Medicine, Stanford University, Stanford, CA, USA.
Breast cancer is a highly heterogeneous disease whose prognosis and treatment as defined by the expression of three receptors-oestrogen receptor (ER), progesterone receptor and human epidermal growth factor receptor 2 (HER2; encoded by ERBB2)-is insufficient to capture the full spectrum of clinical outcomes and therapeutic vulnerabilities. Previously, we demonstrated that transcriptional and genomic profiles define eleven integrative subtypes with distinct clinical outcomes, including four ER subtypes with increased risk of relapse decades after diagnosis. Here, to determine whether these subtypes reflect distinct evolutionary histories, interactions with the immune system and pathway dependencies, we established a meta-cohort of 1,828 breast tumours spanning pre-invasive, primary invasive and metastatic disease with whole-genome and transcriptome sequencing.
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January 2025
Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Paris, France.
The replication of the two chromosomes in the pathogenic bacterium Vibrio cholerae is coordinated by the binding of initiator protein RctB to a checkpoint sequence, crtS. Replication of crtS on the primary chromosome (Chr1) triggers replication of the secondary chromosome (Chr2), but the details are poorly understood. Here, we analyze RctB binding patterns in the V.
View Article and Find Full Text PDFNat Commun
January 2025
Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK.
ATR plays key roles in cellular responses to DNA damage and replication stress, a pervasive feature of cancer cells. ATR inhibitors (ATRi) are in clinical development for treating various cancers, including those with high replication stress, such as is elicited by ARID1A deficiency, but the cellular mechanisms that determine ATRi efficacy in such backgrounds are unclear. Here, we have conducted unbiased genome-scale CRISPR screens in ARID1A-deficient and proficient cells treated with ATRi.
View Article and Find Full Text PDFNat Commun
January 2025
DNA Replication Group, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK.
Human DNA licensing initiates replication fork assembly and DNA replication. This reaction promotes the loading of the hMCM2-7 complex on DNA, which represents the core of the replicative helicase that unwinds DNA during S-phase. Here, we report the reconstitution of human DNA licensing using purified proteins.
View Article and Find Full Text PDFCurr Cancer Drug Targets
January 2025
Cancer Research Center, Shantou University Medical College, Shantou 515041, Guangdong, PR China.
Among the Poly(ADP-ribose) Polymerase (PARP) family in mammals, PARP1 is the first identified and well-studied member that plays a critical role in DNA damage repair and has been proven to be an effective target for cancer therapy. Here, we have reviewed not only the role of PARP1 in different DNA damage repair pathways, but also the working mechanisms of several PARP inhibitors (PARPi), inhibiting Poly-ADP-ribosylation (PARylation) processing and PAR chains production to trap PARP1 on impaired DNA and inducing Transcription- replication Conflicts (TRCs) by inhibiting the PARP1 activity. This review has systematically summarized the latest clinical application of six authorized PARPi, including olaparib, rucaparib, niraparib, talazoparib, fuzuloparib and pamiparib, in monotherapy and combination therapies with chemotherapy, radiotherapy, and immunotherapy, in different kinds of cancer.
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